The invention relates to two-cycle, spark ignition engines, and particularly, to improvements thereof.
The typical two-cycle engine requires a mixture of oil and gasoline to be combined with air in the carburetor and supplied to the crankcase via a reed valve arrangement. On the compression stroke, such a mixture of fuel, air, and oil already in the combustion chamber is compressed, while the vacuum formed in the airtight crankcase by movement of the piston draws more of the mixture from the carburetor via the reed valves. At the top of the compression stroke, the pressure stabilizes in the crankcase to close the reed valves, the spark plug is fired, and the piston starts the return (power) stroke. During the return stroke, power is transmitted to the crankshaft and the mixture in the crankcase is compressed by the piston so that, near the bottom of the stroke, the piston uncovers the exhaust port and a fuel transfer port, allowing the pressurized mixture to rush into the combustion chamber and to force the burned gases out of the exhaust port.
Two-stroke engines are plagued by carbn build-up, which results from incomplete combustion of the oil and gasoline that are combined in the fuel tank. The carbon accumulates on the muffler and the exhaust ports and must be cleaned off regularly.
Accordingly, it is an object of this invention to provide a two-stroke engine in which the typical carbon build-up is eliminated by eliminating the need for mixing oil and fuel.
It is another object of this invention to provide for fuel injection to the combustion chamber of a two-stroke engine while lubricating the moving parts thereof via constant circulation and injection of oil into the crankcase thereof.
It is a further object of this invention to provide means for converting a standard two-stroke engine for fuel injection into the combustion chamber and oil injection into the crankcase, while blocking the transfer port to provide separation between the combustion chamber and crankcase.
It is a further object of this invention to provide a novel crankcase venting arrangement for relieving back pressure therein while preventing a loss of oil from an oil circulation system.
It is a further object of this invention to provide a continuously operating air blower attached to the cylinder via an air horn, with a butterly valve controlled by the spark advance mechanism such that air for the combustible mixture is varied in accordance with the requirements of the engine.
It is a further object of this invention to provide a fuel injection, two-cycle engine in which the fuel injection nozzle is protected from direct combustion of the engine.
These and other objects of the invention will become more readily apparent from the following disclosure.
In a preferred embodiment of the invention, a two-stroke engine is provided with oil injection to a crankcase integral with the cylinder wall of a combustion chamber, but separated from the chamber by a reciprocating piston. Fuel is injected into the combustion chamber of the cylinder in a timed relation in accordance with the load requirements of the engine. A continuously operating blower motor provides air to the combustion chamber, for the fuel and air combustible mixture, via a butterly valve attached to the spark advance linkage for proper variation thereof.